Exhaust port structure

ABSTRACT

An exhaust port structure and cylinder head construction for an internal combustion engine in which the exhaust port structure is permitted to attain relatively high temperatures while the exhaust valve and seat are maintained relatively cool. Cooling is achieved by cooling the valve guide structure and overheating of the valve and valve stem is prevented by providing a structure which tends to maintain the valve and its seat in proper alignment regardless of thermal and pressure distortions.

United States Patent 11 1 Bachle 1451 Apr. 24, 1973 1 1 EXHAUST PORT STRUCTURE [75] lnventor: Carl F. Bachle, Grosse Farms, Mich.

Pointe [73] Assignee: Teledyne Industries, Inc., Los Angeles, Calif.

22 Filed: Aug. 18,1970

21 Appl. N0.: 64,782

[52] U.S. Cl. .....123/188 GC, 123/188 S, 123/188 C, 123/188 SC, 123/188 A, 123/4141,

[51] Int. Cl ..F0lp 1/08, FOll 3/00, FOlp 3/14 [58] Field of Search ..123/l88 CC, 188 S, 123/188 C, 188 SA, 188 SC, 188 A, 41.41,

[56] References Cited UNITED STATES PATENTS 1,918,481 7 1933 Moorhouse 123/188 GC 1,442,698 1/1923 Page ....123/41.41 x 1,655,149 1/1928 Lee ..123 41.41

2,070,926 2/1937 Sander ct a1 ..123/41.69

FOREIGN PATENTS OR APPLlCATlONS 284,210 4/1931 ltaly "123/4141 806,393 12/1958 Great Britain. 123/188 S 967,274 10/1950 France 123/188 GC Primary Examiner-Laurence M. Goodridge Assistant ExaminerA. M. Zupcic Att0rney-Hauke, Gifford and Patalidis [57] ABSTRACT An exhaust port structure and cylinder head construction for an internal combustion engine in which the exhaust port structure is permitted to attain relatively high tergperatures while the exhaust valve and seat are maintained relatively cool. Cooling is achieved by cooling the valve guide structure and overheating of the valve and valve stem is prevented by providing a structure which tends to maintain the valve and its seat in proper alignment regardless of thermal and pressure distortions.

14 Claims, 14 Drawing Figures PATENTED R M B 3,728,994

SHEET 1 OF 5 INVENTOR CARL F. BACHLE 2/ 1 Qfarvefj- I WWW I913 SHEET 3 [1F 5 INVENTOR CARL F. BACHLE PAIENTEUAPR 24 1975 3, 728,994

SHEET n -[]F 5 INVENTOR CARL F. BACHLE "BY flaw/6,, GWf

APR 24 m 3. 728, 994

' sum 5 UF 5 INVENTOR CARL F. BACHLE EXHAUST PORT STRUCTURE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to internal combustion engines and more particularly to improvements in the exhaust port area of such engines.

II. The Prior Art One problem in achieving long life for internal combustion engines is associated with overcoming exhaust valve failure and this in turn depends to a large extent on maintaining the valve face and its seat relatively cool. Proper alignment between the exhaust valve and its seat is necessary to maintain the valve cool because in addition to the power which is lost through the open valve a blow torch effect is produced to cause local overheating of the valve seat and the valve stem even up into the valve guide. Such overheating, of course, compounds the problem and thereby substantially reduces the life of the exhaust valve and its associated parts.

Valve leakage is generally caused in the first place by temperature or pressure distortions which tend to cause the valve guide centerline to become misaligned either by cocking or translation to thereby shift the valve face with respect to the seat in the cylinder head of the engine.

In the past this problem has been attacked by attempting to cool the entire exhaust port area and by providing massive cross-sections to give rigidity. If the exhaust port area is properly cooled, temperature distortions will be minimized. Another way to approach this problem is to use more refractory, and hence more expensive, materials to make the parts either less susceptible to distortion, or when distortion occurs less susceptible to failure because of overheating. The first method can only be successful to a degree because regardless of the cooling which is achieved there will still be temperature gradients between different portions of the engine and this will cause some distortion and the problems produced by pressure distortions is not at all taken care of. Distortions of either kind can cause improper seating of the exhaust valve and, as explained above, this will lead to overheating. Also, the heat absorbed by the coolant and the pumping of the coolant to and from the areas to be cooled represents lost horsepower so that if means could be found to overcome the problem of overheating in other ways, a more efficient engine would result. The use of more expensive materials has not been entirely satisfactory either and this, of course, can add substantial costs to the engine.

SUMMARY OF THE INVENTION The present invention provides a solution to this problem by providing a relatively cooler valve, a relatively cooler cylinder head, a relatively cooler valve seat, and an improved valve seating resulting from the prevention of misalignment of the valve guide, valve and valve seat. The exhaust port structure of the invention attains a relatively higher temperature than in commonly used prior art structures.

The term exhaust port structure as herein used is directed to a pipe elbow which conducts the hot waste exhaust gas from the cylinders.

The exhaust valve is supported independently of the exhaust port structure and is kept cool by cooling the valve guide structure which encompasses the stern of the valve and which is constructed of a material having high heat transfer characteristics, such as copper or the like.

To prevent overheating of the valve and the other attendant effects of poor valve seating, such as lost power and improper combustion, as might be caused by thermal and pressure distortions affecting the valve and its seat, a construction is provided in which these distortions are permitted to occur, but in which seating of the valve is maintained regardless of the distortions.

The exhaust valve seat in the cylinder dome is formed as part of the exhaust port structure which in turn has a lower portion joined to the cylinder dome of the engine and an upper portion formed intermediate an exhaust pipe and the lower portion. The upper portion of the exhaust port is relatively flexible to absorb thermal and pressure distortions without affecting the valve seat formed in the lower portion. The valve guide structure is joined, independently of the exhaust port wall, by a tubular member directly to the exhaust valve seat in the cylinder dome of the engine so that changes in the position of the valve Valve leakage is generally caused in the first place by temperature or pressure distortions which tend to cause the valve guide centerline to become misaligned either by cocking or translation to thereby shift the valve face with respect to the seat in the cylinder head of the engine.

In the past this problem has been attacked by attempting to cool the entire exhaust port area and by providing massive cross-sections to give rigidity. If the exhaust port area is properly cooled, temperature distortions will be miminized Another way to approach this problem is to use more refractory, and hence more expensive, materials to make the parts either less susceptible to distortion, or when distortion occurs less susceptible to failure because of overheating. The first method can only be successful to a degree because regardless of the cooling which is achieved there will still be temperature gradients between different portions of the engine and this will cause some distortion and the problems produced by pressure distortions is not at all taken care of. Distortions of either kind can cause imporper seating of the exhaust valve and, as explained above, this will lead to overheating. Also, the heat absorbed by the coolant and the pumping of the coolant to and from the areas to be cooled represents lost horsepower so that if means could be found to overcome the problem of overheating in other ways, a more efficient engine would result. The use of more expensive materials has not been entirely satisfactory either and this, of course, can add substantial costs to the engine.

SUMMARYOF THE INVENTION The present invention provides a solution to this problem by providing a relatively cooler valve, a relatively cooler cylinder head, a relatively cooler valve seat, and an improved valve seating resulting from te prevention of misalignment of the valve guide, valve and valve seat. The exhaust port structure of the invention attains a relatively higher temperature than in commonly used prior art structures.

The term exhaust port structure as herein used is directed to a pipe elbow which conducts the hot waste exhaust gas from the cylinders.

The exhaust valve is supported independently of the exhaust port structure and is kept cool by cooling the valve guide structure which encompasses the stem of the valve and which is constructed of a material having high heat transfer characteristices, such as copper or the like.

To prevent overheating of the valve and the other attendant effects of poor valve seating, such as lost power and improper combustion, as might be caused by thermal and pressure distortions affecting the valve and its seat, a construction is provided in whch these distortions are permitted to occur, but in which seating of the valve is maintained regardless of the distortions.

The exhaust valve seat in the cylinder dome is formed as part of the exhaust port structure which in turn has a lower portion joined to the cylinder dome of the engine and an upper portion formed intermediate an exhaust pipe and the lower portion. The upper portion of the exhaust port is relatively flexible to absorb thermal and pressure distortions without effecting the valve seat formed in the lower portion. The valve guide structure is joined, independently of the exhaust port wall, by a tubular member directly to the exhaust valve seat in the cylinder dome of the engine so that changes in the position of the valve seat in the cylinder dome, as caused by distortions of the cylinder dome, will also produce corresponding changes in the position of the valve guide structure to thereby maintain alignment of the exhaust valve with its seat in the cylinder dome.

A misalignment compensating seal is provided between the upper portion of the exhaust port wall and the valve stem and is formed to provide a spherical alignment, universal fit between the exhaust port structure and the valve stem so that distortions in the exhaust port structure do not affect the centerline of the valve stem.

DESCRIPTION OF THE DRAWINGS A more complete understanding of the present invention can be achieved upon reference to the follow ing description of several preferred embodiments thereof. The description makes reference to the accompanying drawings in which like reference characters refer to like parts throughout the several views and in which:

FIG. 1 is a cross sectional view of a portion of an internal combustion engine illustrating one preferred embodiment of the present invention;

FIG. 2 is a transverse cross sectional view taken substantially on the line 2-2 of FIG. 1;

FIG. 3 is an enlarged perspective view of one of the elements ofthe assembly shown in FIG. 1;

FIG. 4 is an enlarged fragmentary cross sectional view of a portion of the structure shown in FIG. 1;

FIG. 5 is an exploded perspective view of the assembly illustrated in FIG. 1;

FIG. 6 is a view similar to FIG. 1, but illustrating another preferred embodiment of the present invention;

FIG. 7 is a transverse cross sectional view taken substantially on line 7-7 of FIG. 6;

FIG. 8 is a fragmentary cross sectional view illustrating a preferred modification of a portion of the structure illustrated in FIGS. 1 and 6;

FIG. 9 is a view Similar to FIG. 8, but illustrating another preferred modification of the structure illustrated therein;

FIG. 10 is another view similar to FIG. 8 but illustrating still another preferred modification of the structure illustrated therein;

FIG. 11 is another view similar to FIG. 8 but illustrating yet another preferred modification of the structure illustrated therein;

FIG. 12 is an enlarged fragmentary view of a portion of the structure shown in FIG. 8;

FIG. 13 is a view similar to FIGS. 1 and 6 but illustrating still another preferred embodiment of the present invention; and

FIG. 14 is a perspective view of the assembly shown in FIG. 13.

DESCRIPTION OF SEVERAL PREFERRED EMBODIMENTS .Now referring to the drawings for a more detailed description of the present invention, one preferred embodiment thereof is illustrated in FIGS. ll-5 as being formed in a cylinder dome 10 of an internal combustion engine. A cylinder 12 is formed in the usual manner in the cylinder dome 10. An opening 16 is formed in the cylinder dome 10 and an exhaust port structure 18 is disposed within the opening 15 and is secured to the dome 10 along adjacent faces 202l preferably by welding, although it is apparent that other means such as casting in one piece could be utilized as well.

It is important to note at this point that where the words joined or secured are used throughout this specification that this is intended also to include constructions in which the pieces are integrally formed.

A substantially cylindrical tubular member 22 has its inner end secured to a flange 23 (FIG. 5) formed on the exhaust port structure 18 by welding or the like along the inner edge 25 of the tubular member 22 and of the flange 23.

The exhaust port structure 18, as can best be seen in FIGS. 1, 2 and 5, preferably comprises an inner thickened portion 18A in the area of the juncture with the dome 10. A valve seat 26 is formed in inner portion 18A of the exhaust port structure 18 and an exhaust valve 28 has a head 29 with a face 30 adapted to engage and disengage from the seat 26 upon actuation by conventional actuating means (not shown). The exhaust port structure 18 is formed with an outer portion 18B of reduced thickness and which defines a walled conduit 32 which when the exhaust valve 28 is in an open position connects the cylinder 12 with an exhaust pipe 34 through a tubular extension 36 of the exhaust port structure 18.

An opening 38 is formed in the outer portion 188 of the exhaust port structure 18 concentric with the valve seat 26. As can best be seen in FIG. 4, the opening 38 is defined by an edge of the outer portion 18B having a first axially extending annular surface 40 joined to a second axially extending annular surface 4-2 by a radially extending annular surface 44. A thimble-shaped or generally tubular shaped misalignment compensating seal 46 has an upper radially outwardly extended rounded edge 48 so that the edge 48 and the surfaces 40, 42 and 44 form a universal spherical alignment fit between the misalignment compensating seal 46 and the exhaust port structure 18, while retaining the seal 46 in place in the opening 38. The seal 46 is formed with a central opening 49 formed in an inner base portion 56 and defined by a rounded edge 51 which receives the stem 52 of the valve 28 and which provides a universal spherical alignment fit between the seal 46 and valve stem 52. The edge 48 is preferably formed on a radius having its center on the centerline of the valve stem 52 and is press fitted against the surface 40 of the exhaust port structure 18. The base portion 50 as can best be seen in FIG. 3 is of a smaller diameter than the upper or outer edge of the seal 46.

The tubular member 22 has portions of the sidewall removed, as shown at 54 and as can best be seen in FIG. 5, to provide cooling passages and toprovide a means for the extension 36 to extend through the tubular member 22. The member 22 is preferably constructed of high strength material, such as steel, and is provided at its upper edge with an annular recess 56 which receives the upper edge of a finned valve guide member 56. The member 58 is preferably constructed of a material having high heat transfer capabilities, such as copper or the like, and is supported solely by the upper edge of the tubular member 22. The member 56 preferably has a center section 60 for receiving the valve stem 52. The center section 60 extends down into the interior of the misalignment compensating seal 46, as can best be seen in FIG. 1, but does not contact the seal 46 so that there will be a heat transfer barrier in the form of the space 59 between the seal 46 and the valve guide structure 68. Cooling air is preferably directed to the space 61 defined by the outer surface of the member 58 by conventional means not shown. A plate member 62, secured to the upper edge of the tubular member 22 by a plurality of threaded fasteners 64 closes the top of the tubular member 22. Conventional valve springs 66 retain the valve 28 in a closed position except when it is opened by conventional means (not shown).

The cylinder head and exhaust valve assembly ar rangement which has been described is a substantial departure from conventional assemblies. l-leretofore to maintain the exhaust valve cool and'seating properly, it has been thought necessary to design the engine to produce optimum cooling of the entire exhaust port area. The present construction attacks the problem of overheating in a new way. Instead of trying to maintain the entire exhaust port area at cooler temperatures, the exhaust port structure is permitted to achieve relatively high temperatures, while the exhaust valve is maintained relatively cool. In addition, overheating of the valve as caused by improper alignment between the valve and the seat in the cylinder dome is minimized. This is accomplished by mounting the valve seat 26 and the valve guide structure 58 to the cylinder dome 10, such that alignment between the valve seat 26 and the valve stem 62 will be maintained regardless of the distortions occurring in the cylinder dome, and thus, even though the valve seat 26 and the valve stem 52 may be displaced either by cocking or by translation, the valve 26 will still seatproperly in the seat 26.

The thickened inner portion 18A of the exhaust port structure lift is securely joined to the cylinder dome 10. Therefore, distortions of the cylinder dome 110 as caused by thermal differences or combustion pressure will produce changes in the position of the valve seat 26. The tubular member 22 is also securely joined to the valve seat 26 in the cylinder dome 10 so that distortions of the dome 10 will likewise affect the centerline of the tubular member 22. The intended results will be achieved if the tubular member 22 is intimately joined to the cylinder dome 10 and although in the drawings this is accomplished by joining the tubular member 22 to the exhaust port structure'lfi it could also be accomplished by joining the tubular member 22 directly to the cylinder dome 10. Changes in the position of the tubular member will produce corresponding changes in the position of the valve guide structure so that the centerline of the valve member 28 will follow the changes in the position of the valve seat 26 in the cylinder dome It] and will be aligned with the valve seat even though the cylinder dome it) may be severely distorted.

Another problem which is solved by the present construction is that caused by the effects of changes in the exhaust port structure 18 on the centerline of the valve 28. The exhaust pipe 34 is necessarily quite long and therefore acts as a lever on the exhaust port structure 18, amplifying distortions produced along the length of exhaust pipe 34 and transmitting these to the exhaust port structure 18. Ordinarily and with a conventional construction, such distortions tend to distort the point of contact between the exhaust port structure 18 and the valve stem 52 to again cause a shifting of the valve 28 and thus an improper seating between the face 30 and the seat 26. The spherical alignment universal fit between the misalignment compensating seal 46 and the exhaust port structure 18 and between the seal 46 and the valve stem 52 permits the distortions of the exhaust port structure 18 to be taken up in this connection without affecting the valve stem 52. Similarly, changes in the position of the seal 46 are not transmitted to either the valve guide structure 58 or the valve stem 52 and, when the valve stem is shifted by movement of the valve guide structure, the seal will move with respect to the exhaust port structure to accommodate this shift.

Finally, it is no longer necessary to cool the entire exhaust port area and the exhaust valve and its seat can be maintained at lower temperatures with less cooling. This is achieved in the present construction by directing air through the openings 54 in the sidewalls of the tubular member 22 and through the finned valve guide member 58. The reduction in the cooling necessary with the present invention results in increased efficiency because of the reduction in lost horsepower due to cooling.

FIGS. 6-7 illustrate another preferred embodiment of the present invention similar to the embodiment of FIGS. 1-5 but in which the exhaust port structure 118 is cast or otherwise formed in the cylinder dome 114. The exhaust port structure 116 is provided with a lower thickened portion 116A in which the valve seat 326 is formed and an upper relatively flexible portion 1188 which supports a misalignment compensating seal 146 by a spherical alignment universal fit in the manner heretofore described with respect to seal 46. The seal 146 is provided with extended sidewalls to protect the valve stem 52 from heat absorption from impinging exhaust gas which is at higher temperatures. instead of the tubular member 22, one or more upstanding arms 122 extend from the cylinder dome 114 and support a cylindrical member 123 in a position upwardly spaced from and concentric with the valve seat 126. The cylindrical member 123 has a lower, inwardly extending flange 124 which coacts with a flange 125 formed on a finned valve guide member 153 to support the member 158 above the valve seat 126. The valve 28 extends through the member 151? and the seal 14 6 in the manner described above with respect to the embodiment of FIGS. 1-5. As can be seen in the drawings, the arm 122 is preferably located away from exhaust pipe side of the exhaust port structure 118. The exhaust pipe side of the exhaust port structure is quite hot and positioning the arm 122 on the opposite side minimizes thermal effects on the arm.

Like the embodiment described above, the construction illustrated in FIGS. 6--'/ acts to assume a position when the cylinder dome bulges as by temperature and pressure increases to maintain the valve seat 126 and the valve 28 in alignment. As the valve seat 126 is moved to a new position, the member 123, through the arm 122, will also move to a new position such that the axes of the valve 28 and the valve seat 126 remain concentric and aligned. The upper support member 130 is joined to the tinned member 158 by a flexible rubberlike oil sealing member 132 so that the support member 130 does not prevent the valve guide member 158 from shifting when the cylinder member 123 moves to a new position. Again sufficient cooling of the valve can be achieved by directing cooling air through the passages formed in the finned member 158.

FIGS. 8-12 illustrate preferred modifications in the construction of the misalignment compensating seal. The seals 246 of FIGS. 8-12 are formed with the universal spherical alignment fit between the upper rounded edge 2418 of the seal member 246 and the exhaust port structure 18 and between the seal 246 and the valve stem 52 as described with respect to the embodiments of FIGS. 1-6. One important function of the seal, which has not been previously mentioned, is that it provides a scraper action as the valve 28 is opened and closed to maintain the valve stem 52 relatively clean of carbon and other deposits. Deposits of carbon on the valve stem 52 can of course cause the valve to stick. The scraper action is achieved by providing a relatively close fit between the valve stem 52 and the edge of the base portion 250 forming the opening 238 and the valve stem 52 and the valve stem 52.

To prevent oil leakage from the clearance between the valve stem 52 and valve guide structure 58 and into the air space 59 and from the air space 59 into the cooling air as well as to prevent gases from escaping from the exhaust port structure 18 into the cooling air, constructions like those shown in FIGS. 8-12 are alternatcs. In the embodiment of FIGS. 8 and 12, this is accomplished by providing a tubular member 2601 press fitted to annular ridges 252 and 264 having spherical contact surface formed on the interior wall of the seal 246 and the outer surface of the finned member 53 respectively to thereby provide a fluid tight seal between these members. In the embodiment of FIG. 9, the tubular member 260 is replaced by a bellows member 360 to reduce the need for close tolerance machining but, other than this, bellows member 3&0 functions the same as the tubular member 260.

FIGS. 10-11 illustrate modifications in which a washer 270, preferably constructed of stellite or similar material, is disposed between the lower end of the valve guide structure 58 and the base 250 to act as the seal and to provide the carbon scraping action. In the embodiment of FIG. 10, a bellows member 272 is disposed between the washer 270 and the seal 2 while in the embodiment of FIG. 11 the bellows member 272 is eliminated. The seals provided by the embodiments of FIGS. 8-11 not only prevent oil leakage into the exhaust gases but also of course prevent exhaust gases from mixing with the air which is being used to cool the valve guide structure.

FIGS. 13 and 14 illustrate an embodiment of the present invention which includes an exhaust port struc ture 218 similar in construction to the exhaust port structure 18 of the embodiment of FIGS. 1-5 but in which the finned cooling member 258 and thus the valve 28 is supported in a manner similar to that illustrated in FIGS. 6-7.

The exhaust port structure 218 is provided with a lower thickened portion 218A in which the valve seat 226 is formed and an upper relatively flexible portion 218B which supports a misalignment compensating seal 246 in the manner described above.

The exhaust port structure 218 is secured to the cylinder dome 210 as by welding or the like. As can best be seen in FIG. 14, a pair of arms 222 extend upwardly from the cylinder dome 210 on opposite sides of the exhaust port structure to support a rocker arm housing 230. As can best be seen in FIG. 13, a lower portion 232 of the housing 230 is provided with an opening 234 concentric with the valve seat 226. The valve guide member 258 extends through the opening 230 and the stem 252 of valve 28 extends through the valve guide member.

Again the embodiment of FIGS. 13 and 14 acts to assume a position when the cylinder dome bulges as by temperature and pressure increases to maintain the valve seat 226 and the valve 28 in alignment. This is accomplished through the arms 222.

It is apparent that a new approach to the problem of exhaust valve failure has been disclosed. The exhaust valve is maintained at relatively cool temperatures without attempting to cool the entire exhaust port area. To prevent poor engine operation and exhaust valve overheating which can be caused by improper seating between the exhaust valve and its seat, a structure is provided which maintains proper seating regardless of the thermal and pressure distortions produced in the exhaust port area.

While I have described several embodiments of my invention, it is also apparent that many changes can be made therein without departing from the spirit of the present invention or the scope of the appended claims.

lclaim:

1. In an internal combustion engine having a cylinder, a cylinder dome defining the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, a valve seat situated in the cylinder dome communicating with said cylinder, valve guide means for guiding movements of said valve, means for actuating said valve in timed sequence to engage and disengage from said valve seat, the improvement comprising:

an exhaust port structure secured to said cylinder dome and extending therefrom to form an exhaust passage,

said port structure being formed with an opening and the stem of said valve extending through said opening to engage with and disengage from said valve seat upon said valve being actuated by said actuating means,

the portion of said exhaust port structure intermediate said valve seat and said valve stem being relatively flexible to absorb distortions as caused by heat or other stresses, and

means disposed intermediate said valve guide means and said valve seat and extending between the edge of said port structure forming said opening and said valve stem to provide a universal alignment connection therebetween whereby distortions in said exhaust port structure are not transmitted to said valve stem.

2. The invention as defined in claim 1 and in which said last mentioned means comprises a thimble-shaped misalignment compensating member having an upper radially outwardly extending spherical edge engaging with an axially extending annular surface of said exhaust port structure to form said universal alignment connection.

3. The invention as defined in claim 2 and in which said misalignment compensating member includes a portion engaging the surface of the stem with minimum clearance of said valve to scrape clean said surface as said valve is moved between an open and a closed position.

4. In an internal combustion engine having a cylinder, an exhaust valve for said cylinder, a valve guide for guiding reciprocating movement of the stem of said valve, and a valve seat for the seating of the head of said valve, the improvement which comprises:

a curved exhaust conduit provided with an inlet in which said seat is situated, an outlet and an opening intermediate said inlet and said outlet;

a generally thimble-shaped misalignment compensating seal member provided with an opening at the apex thereof for movement of said stem therethrough; said member being unattachedly supported by said exhaust conduit and, together with said valve stem, substantially closing said opening in said exhaust conduit, said tubularshaped member positioned with a concave side facing said valve guide means;

means rigidly connecting said valve seat with said valve guide means such that tilting of said valve seat will effect an accommodating tilt of said valve guide; and

cooling means for cooling said valve guide.

5. in an internal combustion engine having a cylinder, a cylinder dome defining the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, said valve having a stem, means for actuating said valve in timed sequence, a valve seat opening to said cylinder and forming a passage connected with said cylinder through said valve seat; the improvement comprising:

valve guide structure for supporting said valve in position to engage and disengage from said valve seat upon actuation by said actuating means and including means defining a cooling air space about said valve stem,

said valve guide structure comprising a finned cooling member encompassing the stem of said valve,

support means for said valve guide structure, said support means being secured to said cylinder dome;

exhaust port structure for conducting the waste combustion products from said cylinder, an opening in said exhaust port structure concentric with respect to said valve seat, the stem of said valve extending through said opening,

a seal disposed between said valve stem and said exhaust port structure to prevent fluid leakage past said opening and into said cooling air space.

6. An internal combustion engine having a cylinder,

a cylinder dome defined in the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, a valve seat situated in the cylinder dome communicating with said cylinder, valve guide means for guiding movements of said valve means, means for actuating said valve in timed sequence to engage and disengage from said valve seat, the improvement comprising:

an exhaust port structure secured to said cylinder dome and extending therefrom to form an exhaust path, said exhaust port structure being formed with an opening, the stem of said valve extending through said opening so that the valve engages with and disengages from said valve seat upon said valve being actuated by said actuating means,

the portion of said exhaust port structure intermediate said valve seat and said valve stem being relatively flexible to absorb distortions caused by heat or other stresses, and

means extending between the edge of said port structure forming said opening and said valve stem to provide a universal alignment connection therebetween whereby distortions in said exhaust port structure are not directly transmitted to said valve stem, said last mentioned means comprising a thimble-shaped misalignment compensating member having an upper radially outwardly spherical edge engaging with an axially extending annular surface of said exhaust port structure to form said universal alignment connection and including a portion engaging the surface of the stem with a minimum clearance of said valve to scrape clean said surface as said valve is moved between an open and closed position,

a tinned cooling member supporting said valve and disposed outwardly of said exhaust port structure and compensating member, and a seal carried by said misalignment compensating member to prevent fluid leakage from said exhaust port structure into the area of said cooling member.

'7. An internal combustion engine having a cylinder,

a cylinder dome defined in the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, a valve seat situated in the cylinder dome communicating with said cylinder, valve guide means for guiding movements of said valve means, means for actuating said valve in timed sequence to engage and disengage from said valve seat,

the improvement comprising:

an exhaust port structure secured to said cylinder dome and extending therefrom to form an exhaust path, said exhaust port structure being formed with an opening, the stem of said valve extending through said opening so that the valve engages with and disengages from said valve seat upon said valve being actuated by said actuating means,

the portion of said exhaust port structure intermediate said valve seat and said valve stem being relatively flexible to absorb distortions caused by the heat or other stresses, and

means extending between the edge of said port structure forming said opening and said valve stem to provide a universal alignment connection therebetween whereby distortions in said exhaust port structure are not directly transmitted to said valve stem, said last mentioned means comprising a thimble-shaped misalignment compensating member having an upper radially outwardly sperhical edge engaging with an axially extending annular surface of said exhaust port structure to form said universal alignment connection and including a portion engaging the surface of the stem with a minimum clearance of said valve to scrape clean said surface as said valve is moved between an open and closed position,

support means secured to said cylinder dome to support the stem of said valve,

and a finned member carried by said support member and encompaissing said valve seat. 8. In an internal combustion engine having a cylinder, a cylinder dome defining the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, means for actuating said valve in timed sequence, a valve seat opening to said cylinder and forming a passage connected with said cylinder through said valve seat; the improvement comprising:

valve guide structure for supporting said valve in position to engage and disengage from said valve seat upon actuation by said actuating means,

support means mounting said valve guide structure in a manner permitting an accommodating positioning of said valve guide structure upon distortion of said cylinder dome to thereby maintain alignment of said valve with said valve seat;

said valve guide structure comprising a finned cooling member supported by said support means and encompassing the stem of said valve;

means disposed intermediate said valve seat and said valve guide structure to prevent fluid leakage from said passage from impinging upon said valve guide structure.

9. The invention as defined in claim 8 and in which said support means comprises an arm portion extending from said cylinder dome,

10. In an internal combustion engine having a cylinder, a cylinder dome defining the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, means for actuating said valve in timed sequence, a valve seat opening to said cylinder and forming a passage connected with said cylinder through said valve seat; the improvement comprising:

valve guide structure for supporting said valve in position to engage and disengage from said valve seat upon actuation by said actuating means, support means mounting said valve guide structure in a manner permitting an accommodating positioning of said valve guide structure upon distortion of said cylinder dome to thereby maintain alignment of said valve with said valve seat;

said support means comprising a tubular member having a circular end portion joined to and extending from said cylinder dome with the axis of said tubular member corresponding with the axes of said valve and said valve seat. 1 l. The invention as defined in claim 30 and in which said tubular member includes a laterally removed portion, said exhaust port structure extending through said laterally removed portion of said tubular member.

12. In an internal combustion engine having a cylinder, a cylinder dome defining the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, a valve for exhausting waste combustion products from said cylinder, means for actuating said valve in tuned sequence, a valve seat opening to said cylinder and forming a passage connected with said cylinder through said valve seat; the improvement comprising:

valve guide structure for supporting said valve in position to engage and disengage from said valve seat upon actuation by said actuating means,

support means mounting said valve guide structure in a manner permitting an accommodating positioning of said valve guide structure upon distortion of said valve with said valve seat;

means disposed intermediate said valve seat and said guide structure to prevent fluid leakage from said passage from impinging upon said valve guide structure;

exhaust port structure for conducting the waste combustion products from said cylinder, an opening in said exhaust port structure concentric with respect to said valve seat, the stem of said valve extending through said opening; and

said last mentioned means being carried by said exhaust port structure to engage the surface of said valve stem as said valve is opened and closed to scrape and thereby clean the surface of said valve stem.

13. The invention as defined in claim 12 and in which said support means comprises a pair of arm members extending from said cylinder dome.

14. The invention as defined in claim 12 and including a cooling air space encompassing said valve guide structure. 

1. In an internal combustion engine having a cylinder, a cylinder dome defining the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, a valve seat situated in the cylinder dome communicating with said cylinder, valve guide means for guiding movements of said valve, means for actuating said valve in timed sequence to engage and disengage from said valve seat, the improvement comprising: an exhaust port structure secured to said cylinder dome and extending therefrom to form an exhaust passage, said port structure being formed with an opening and the stem of said valve extending through said opening to engage with and disengage from said valve seat upon said valve being actuated by said actuating means, the portioN of said exhaust port structure intermediate said valve seat and said valve stem being relatively flexible to absorb distortions as caused by heat or other stresses, and means disposed intermediate said valve guide means and said valve seat and extending between the edge of said port structure forming said opening and said valve stem to provide a universal alignment connection therebetween whereby distortions in said exhaust port structure are not transmitted to said valve stem.
 2. The invention as defined in claim 1 and in which said last mentioned means comprises a thimble-shaped misalignment compensating member having an upper radially outwardly extending spherical edge engaging with an axially extending annular surface of said exhaust port structure to form said universal alignment connection.
 3. The invention as defined in claim 2 and in which said misalignment compensating member includes a portion engaging the surface of the stem with minimum clearance of said valve to scrape clean said surface as said valve is moved between an open and a closed position.
 4. In an internal combustion engine having a cylinder, an exhaust valve for said cylinder, a valve guide for guiding reciprocating movement of the stem of said valve, and a valve seat for the seating of the head of said valve, the improvement which comprises: a curved exhaust conduit provided with an inlet in which said seat is situated, an outlet and an opening intermediate said inlet and said outlet; a generally thimble-shaped misalignment compensating seal member provided with an opening at the apex thereof for movement of said stem therethrough; said member being unattachedly supported by said exhaust conduit and, together with said valve stem, substantially closing said opening in said exhaust conduit, said tubular-shaped member positioned with a concave side facing said valve guide means; means rigidly connecting said valve seat with said valve guide means such that tilting of said valve seat will effect an accommodating tilt of said valve guide; and cooling means for cooling said valve guide.
 5. In an internal combustion engine having a cylinder, a cylinder dome defining the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, said valve having a stem, means for actuating said valve in timed sequence, a valve seat opening to said cylinder and forming a passage connected with said cylinder through said valve seat; the improvement comprising: valve guide structure for supporting said valve in position to engage and disengage from said valve seat upon actuation by said actuating means and including means defining a cooling air space about said valve stem, said valve guide structure comprising a finned cooling member encompassing the stem of said valve, support means for said valve guide structure, said support means being secured to said cylinder dome; exhaust port structure for conducting the waste combustion products from said cylinder, an opening in said exhaust port structure concentric with respect to said valve seat, the stem of said valve extending through said opening, a seal disposed between said valve stem and said exhaust port structure to prevent fluid leakage past said opening and into said cooling air space.
 6. An internal combustion engine having a cylinder, a cylinder dome defined in the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, a valve seat situated in the cylinder dome communicating with said cylinder, valve guide means for guiding movements of said valve means, means for actuating said valve in timed sequence to engage and disengage from said valve seat, the improvement comprising: an exhaust port structure secured to said cylinder dome and extending therefrom to form an exhaust path, said exhaust port structure being formed with an opening, the stem of said valve extending through said opening so that the valve engages with and disengages from said valve seat upon said valve being actuated by said actuating means, the portion of said exhaust port structure intermediate said valve seat and said valve stem being relatively flexible to absorb distortions caused by heat or other stresses, and means extending between the edge of said port structure forming said opening and said valve stem to provide a universal alignment connection therebetween whereby distortions in said exhaust port structure are not directly transmitted to said valve stem, said last mentioned means comprising a thimble-shaped misalignment compensating member having an upper radially outwardly spherical edge engaging with an axially extending annular surface of said exhaust port structure to form said universal alignment connection and including a portion engaging the surface of the stem with a minimum clearance of said valve to scrape clean said surface as said valve is moved between an open and closed position, a finned cooling member supporting said valve and disposed outwardly of said exhaust port structure and compensating member, and a seal carried by said misalignment compensating member to prevent fluid leakage from said exhaust port structure into the area of said cooling member.
 7. An internal combustion engine having a cylinder, a cylinder dome defined in the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, a valve seat situated in the cylinder dome communicating with said cylinder, valve guide means for guiding movements of said valve means, means for actuating said valve in timed sequence to engage and disengage from said valve seat, the improvement comprising: an exhaust port structure secured to said cylinder dome and extending therefrom to form an exhaust path, said exhaust port structure being formed with an opening, the stem of said valve extending through said opening so that the valve engages with and disengages from said valve seat upon said valve being actuated by said actuating means, the portion of said exhaust port structure intermediate said valve seat and said valve stem being relatively flexible to absorb distortions caused by the heat or other stresses, and means extending between the edge of said port structure forming said opening and said valve stem to provide a universal alignment connection therebetween whereby distortions in said exhaust port structure are not directly transmitted to said valve stem, said last mentioned means comprising a thimble-shaped misalignment compensating member having an upper radially outwardly sperhical edge engaging with an axially extending annular surface of said exhaust port structure to form said universal alignment connection and including a portion engaging the surface of the stem with a minimum clearance of said valve to scrape clean said surface as said valve is moved between an open and closed position, support means secured to said cylinder dome to support the stem of said valve, and a finned member carried by said support member and encompaissing said valve seat.
 8. In an internal combustion engine having a cylinder, a cylinder dome defining the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, means for actuating said valve in timed sequence, a valve seat opening to said cylinder and forming a passage connected with said cylinder through said valve seat; the improvement comprising: valve guide structure for supporting said valve in position to engage and disengage from said valve seat upon actuation by said actuating means, support means mounting said valve guide structure in a manner permitting an accommodating positioning of said valve guide structure upon distortion of said cylinder dome to thereby maintain alignment of said valve with said valve seat; said valve guide structure comprising a finned cooling member supported by said support means and encompassing the stem of said valve; meanS disposed intermediate said valve seat and said valve guide structure to prevent fluid leakage from said passage from impinging upon said valve guide structure.
 9. The invention as defined in claim 8 and in which said support means comprises an arm portion extending from said cylinder dome.
 10. In an internal combustion engine having a cylinder, a cylinder dome defining the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, means for actuating said valve in timed sequence, a valve seat opening to said cylinder and forming a passage connected with said cylinder through said valve seat; the improvement comprising: valve guide structure for supporting said valve in position to engage and disengage from said valve seat upon actuation by said actuating means, support means mounting said valve guide structure in a manner permitting an accommodating positioning of said valve guide structure upon distortion of said cylinder dome to thereby maintain alignment of said valve with said valve seat; said support means comprising a tubular member having a circular end portion joined to and extending from said cylinder dome with the axis of said tubular member corresponding with the axes of said valve and said valve seat.
 11. The invention as defined in claim 10 and in which said tubular member includes a laterally removed portion, said exhaust port structure extending through said laterally removed portion of said tubular member.
 12. In an internal combustion engine having a cylinder, a cylinder dome defining the upper portion of said cylinder, a valve for exhausting waste combustion products from said cylinder, a valve for exhausting waste combustion products from said cylinder, means for actuating said valve in tuned sequence, a valve seat opening to said cylinder and forming a passage connected with said cylinder through said valve seat; the improvement comprising: valve guide structure for supporting said valve in position to engage and disengage from said valve seat upon actuation by said actuating means, support means mounting said valve guide structure in a manner permitting an accommodating positioning of said valve guide structure upon distortion of said valve with said valve seat; means disposed intermediate said valve seat and said guide structure to prevent fluid leakage from said passage from impinging upon said valve guide structure; exhaust port structure for conducting the waste combustion products from said cylinder, an opening in said exhaust port structure concentric with respect to said valve seat, the stem of said valve extending through said opening; and said last mentioned means being carried by said exhaust port structure to engage the surface of said valve stem as said valve is opened and closed to scrape and thereby clean the surface of said valve stem.
 13. The invention as defined in claim 12 and in which said support means comprises a pair of arm members extending from said cylinder dome.
 14. The invention as defined in claim 12 and including a cooling air space encompassing said valve guide structure. 